/**
 * Copyright 2007-2009 Vidar Svansson
 *
 * This file is part of JAdapter.
 *
 * JAdapter is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * JAdapter is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with JAdapter.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.jadapter.func;

import java.util.Iterator;

/**
 * Iterator that filters out elements.
 * @author Vidar Svansson
 * 
 * @since 0.3
 * @param <T>
 */

public class FilterIterator<T> implements Iterator<T> {
    private Iterator<? extends T> iterator;
    private Filter<T> filter;
    private boolean hasNext = false;
    private T next = null;

    public FilterIterator(Iterable<? extends T> iterable, Filter<T> filter) {
        this.iterator = iterable.iterator();
        this.filter = filter;
        forward();
    }
    
    protected void forward() {
        hasNext = false;
        T current;            
        while (!hasNext && iterator.hasNext()) {
            current = iterator.next();
            if (filter == null || filter.filter(current)) {
                next = current;                    
                hasNext = true;
            }
        }
    }
    
    public T next() {
        T ret = next;
        forward();
        return ret;
    }

    public boolean hasNext() {
        return hasNext;
    }

    public void remove() {
        throw new UnsupportedOperationException();
    }      
}
